1. Field of the Invention
The present invention relates mainly to a converter support structure gliding in contact over a recording medium. More specifically, the present invention relates to a gliding converter support structure for a magnetic recording device or an optomagnetic recording and reproducing device used as an external storage device for a computer, or as a recording and reproducing device for music or video signals or other information.
2. Description of the Prior Art
A common example of a conventional gliding converter support structure is a magnetic core support structure for magnetic recording. Magnetic tape and flexible disks used to be the main media using such a structure, but recently minidisks (referred to as xe2x80x9cMDsxe2x80x9d in the following) are becoming increasingly popular as optomagnetic recording media for recording music. A prerequisite for MDs is the use of a gliding magnetic head slider for optomagnetic overwriting using a modulated magnetic field, and the disk has a gliding film for gliding. The following is a discussion of a magnetic head slider for MDs serving as a converter support structure.
A conventional gliding magnetic head slider for optomagnetic recording, particularly for MDs, is disclosed in Publication of Unexamined Japanese Patent Application No. Hei 6-195851. Its overall structure is shown in FIG. 4(a).
In FIG. 4(a), numeral 101 denotes a slider means serving as a converter support structure, on which a magnetic core 102 serving as a converter, and a coil (not shown in the drawings) are installed. Publication of Unexamined Japanese Patent Application No. Hei 7-129902 discloses details concerning the slider means 101, which are illustrated in FIG. 4(b). A cylindrical surface 101a is formed as a gliding surface on a surface of the slider means that opposes the disk. Numeral 102a denotes the magnetic pole of a magnetic core 102 that is exposed toward the side of the disk.
Publication of Unexamined Japanese Patent Application No. Hei 6-195851 discloses the relation between the cylindrical surface 101a and the magnetic pole 102a, as shown in FIG. 5. FIG. 5 is a drawing of the slider means 101 taken from the opposite side of the surface opposing the disk.
In FIG. 5, A denotes the tangent line to the disk track of the center point of the magnetic pole 102a, and B denotes the disk radius through the magnetic pole 102a. 
Contact region 101b is the region of the cylindrical surface 101a contacting the disk""s gliding film. The contact line C101 is defined as the line passing along the center of the contact region 101b. The contact line C101 is arranged so that it defines a certain angle xcfx86 with the tangent A through the center of the magnetic core 102a during regular contact with the disk. With such a tilted arrangement, the contact line C101 can be arranged substantially parallel to the tangent direction of the disk track in the contact region 101b, which reduces the gliding width (that is, the width of the contact region 101b in the direction perpendicular to the gliding direction). In FIG. 5, the magnetic pole 102a is shown as if all parts on the side opposing the disk are transparent.
The slider means 101, which includes the cylindrical surface 101a, is made of a resin material that is resistant against abrasion with the disk surface and very smooth, so that it prevents damage due to abrasion between the slider and the disk.
The pressing force of a spring portion 104, which serves as a loading means, causes the contact region 101b of the cylindrical surface 101a to glide in contact with the gliding film of the disk, so that the magnetic pole 102a is positioned near the disk""s recording film. The disk may be tilted due to surface warps and distortions, causing positional misalignments but, contact can be maintained because the gimbal 103 is deformed with respect to tilting around an axis orthogonal to the contact line C101 in FIG. 5, and the contact region shifts with respect to tilting around an axis parallel to the contact line C101 (rolling motion). In this situation, thermomagnetic recording is performed by applying to the recording film, which has been heated with focused laser light, a modulation magnetic field with a coil (not shown in the drawings) from the magnetic pole 102a. 
Together with the optical head, the slider means 101 can move over the disk in the radial direction B in FIG. 5, so that a recording magnetic field can be applied to any portion of the disk.
However, a conventional magnetic head as described above poses the following problems.
If C102 is the line segment that passes through the center of the magnetic pole 102a in parallel to the contact line C101, then C101 and C102 are separated by the distance d. The value of d varies with shifts of the contact region 101b, but it is preferable that it is zero during regular operation.
The reason for this is that if the disk is tilted around an axis parallel to the contact line C101 for an angle xcex8, the contact line C101 shifts, and the distance d changes. When the original of d is d0 and the shift portion is dxe2x80x2, then the largest possible change of the distance between the magnetic pole 102a and the disk is (dxe2x80x2+d0)sin xcex8.
This change of distance causes variations in the size of the magnetic field generated by the magnetic pole 102a, and a field that is too small may lead to recording errors. Therefore, it is necessary to run an additional current through the coil to compensate for the shift portion, which leads to an increase in the consumed power.
Moreover, since the gliding surface 101a is a cylindrical surface, the region of contact with the disk is large, and the viscous resistance with the gliding film of the disk is large, so that the load on the spindle motor increases and causes an increase in the consumed power.
Moreover, the cylindrical surface 101a easily gathers dust, and when dust has accumulated near the center of the contact region 101b for example, it causes a large positional change, changing the distance between the disk and the magnetic pole 102a. Since the contact region is large, the accumulation of dust occurs relatively easily.
As long as the direction in which the slider means 101 moves when accessing the disk in a radial direction is not orthogonal to the contact line C101, it is impossible to consistently match the direction of the contact line C101 with the direction tangential to the track in the contact region. In other words, with this configuration, when accessing the disk in a radial direction, in almost all positions in radial direction of the disk, the contact line C101 has a certain tilt with respect to the direction tangential to the track. This means that the slide width of the contact region 101b (that is, the width in the direction orthogonal to the slide direction of the contact region 101b) is always larger than the width of the contact region 101b in the direction perpendicular to the contact line C101, which becomes a cause for a large sliding resistance and the accumulation of dust.
It is an object of the invention to solve the above problems of the prior art, and to provide a converter support structure with a simple configuration, high efficiency, and low sliding resistance, that does not easily accumulate dust.
The following describes a configuration of the present invention that achieves these objects.
A converter support structure according to a first configuration of the present invention supports a converter for recording/reproducing while moving relative to a recording medium, and includes at least two protrusion portions for maintaining the converter in a predetermined position with respect to the recording medium by contacting the recording medium. The protrusion portions are arranged substantially in parallel to the direction in which the converter moves relative to the recording medium, and a central portion of a region in which the converter interacts with the recording medium is arranged substantially on a line that passes through centers of regions where the protrusion portions contact the recording medium.
A converter support structure according to a second configuration of the present invention supports a converter for recording/reproducing while moving relative to a recording medium, and includes a protrusion portion for maintaining the converter in a predetermined position with respect to the recording medium by contacting the recording medium. A long axis of a region of contact between the protrusion portion and the recording medium is arranged substantially in parallel to the direction in which the converter moves relative to the recording medium, and a central portion of a region in which the converter interacts with the recording medium is arranged substantially on this long axis.
The converter support structures of the present invention reduce variations in the relative distance between the converter and the recording medium because at least two protrusion portions are arranged substantially in parallel to the direction in which the converter moves relative to the recording medium, and a central portion of the regions in which the converter interacts with the recording medium is arranged substantially on a line that passes through centers of regions where the protrusion portions contact the recording medium, or a long axis of a region of contact between the protrusion portions and the recording medium is arranged substantially in parallel to the direction in which the converter moves relative to the recording medium, and a central portion of a region in which the converter interacts with the recording medium is arranged substantially on this long axis.
In the first configuration, it is preferable that the protrusion portions are two protrusion portions. Moreover, it is preferable that the protrusion portions include a spherical surface. Moreover, in the first and in the second embodiment, it is preferable that the region where the protrusion portion contacts the recording medium is substantially elliptical. With these configurations, the sliding resistance with the recording medium is reduced and the accumulation of dust is reduced, because the region of contact between the protrusion portion and the surface of the recording medium is reduced and the sliding width is reduced. Furthermore, these improved configurations can be manufactured without posing any new difficulties.